Semi-inclusive studies of semileptonic Bs decays at Belle

Abstract

We present an analysis of the semi-inclusive decays Bs→Ds-Xℓ+ν and Bs→Ds∗-Xℓ+ν, where X denotes a final state that may consist of additional hadrons or photons and ℓ is an electron or muon. The studied Bs decays are contained in the 121.4fb-1 Υ(5S) data sample collected by the Belle detector at the KEKB asymmetric-energy e+e- collider. The branching fractions of the decays are measured to be B(Bs→Ds-Xℓ+ν)=[8.2±0.2(stat)±0.6(syst)±1.4(ext)]% and B(Bs→Ds∗-Xℓ+ν)=[5.4±0.4(stat)±0.4(syst)±0.9(ext)]%, where the first two uncertainties are statistical and systematic and the last is due to external parameters. The measurement also provides an estimate of the Bs(∗)B¯s(∗) production cross section, σ(e+e-→Bs(∗)B¯s(∗))=[53.8±1.4(stat)±4.0(syst)±3.4(ext)]pb, at the center-of-mass energy s=10.86GeV.